Radial-mount micro-blower for medical ventilator

Abstract

Title of the Invention: Radial-Mounted Micro-Blower for Medical Ventilator. The invention relates to a micro-blower (1) for a medical ventilator (100) comprising an electric motor (3) arranged in a housing (4) and a volute (2) arranged to overcome the electric motor (3). The motor (3) comprises a rotating drive shaft (15) carrying a vane (5). The volute (2) comprises an internal compartment (9) containing the vane (5). The volute (2) comprises a skirt (10) forming a sleeve around the housing (4) and attached to said housing (4). Medical ventilator (100) comprising such a micro-blower (1). Abstract figure: Fig. 3

Description

Title of the invention: Radial-mounted micro-blower for medical ventilator

[0001] The invention relates to a motorized micro-blower for a medical ventilator, i.e. a respiratory assistance device, used to treat respiratory pathologies in humans, and a medical ventilator equipped with such a motorized micro-blower.

[0002] In order to assist certain patients in their respiratory function, respiratory assistance or assisted ventilation devices are used, often called "medical ventilators" or "ventilation devices", delivering a respiratory gas, such as air, at a non-zero flow rate and / or at a pressure higher than atmospheric pressure (> 1 atm).

[0003] To do this, a medical ventilator uses a micro-blower, also called a "compressor" or "turbine", used to suck in ambient air and deliver it at a given pressure to patients. The air can be supplemented with additional oxygen, particularly when the patient must receive, as part of their treatment, a proportion of oxygen greater than 21% by volume.

[0004] The air is sucked in by the motorized micro-blower using one (or more) impellers arranged on a rotating shaft or axis driven in rotation by an electric motor, the impeller being arranged to be mobile in rotation in the internal compartment of a volute surmounting the engine block, i.e. the engine surrounded by its peripheral casing.

[0005] Documents EP-A-2165078, EP-A-2102504, WO-A-2012 / 139681, US-A-2008 / 304986 and WO-A-2013 / 020167 describe micro-blowers of this type and respiratory assistance devices equipped with such micro-blowers.

[0006] A recurring problem is linked to the complexity of assembling the components of the micro-blower and its repeatability in production, which is particularly detrimental to obtaining the expected performance of the micro-blower, due in particular to imperfect assembly causing uncontrolled clearances between the wheel and the volute in particular.

[0007] The present invention aims to solve this problem by proposing an improved micro-blower, in which it is possible to ensure good mounting of the volute around the bladed wheel of the micro-blower, in particular by better controlling the clearances existing between them, in order to guarantee the expected performance of the micro-blower.

[0008] The solution of the invention then relates to a micro-blower for a medical ventilator comprising an electric motor arranged in a casing and a volute arranged so as to surmount the electric motor, in which the electric motor comprises a rotating motor shaft carrying a vaned wheel, and the volute comprises an internal compartment containing the vaned wheel, characterized in that the volute comprises a skirt forming a sleeve around the casing and secured to said casing.

[0009] Depending on the embodiment considered, the micro-blower of the invention may comprise one or more of the following characteristics:

[0010] - the skirt of the volute is arranged at the base of the volute. - the skirt of the volute is formed in one piece with the rest of the volute. - the skirt of the volute is formed from a material having flexibility, in particular particularly a polymer. - the volute skirt comprises several axial tabs, preferably at least three axial tabs in order to ensure that the volute is held securely in position on the engine casing - the skirt has a generally cylindrical shape. - the skirt of the volute comprises several axial tabs crossed by a screw hole, preferably each axial tab comprises a screw hole. - the axial tabs are formed from longitudinal cutouts made in pairs in the wall of the skirt. - the skirt of the volute projects axially away (axis AA) from the upper part of the volute delimiting the internal compartment. - the volute skirt is shaped to allow it to be fitted around the motor casing when the impeller is carried by the motor shaft, i.e. without having to dismantle the impeller. - the skirt is fixed to the casing by screws (or similar) passing through the screw holes carried by the axial tabs. - the motor casing includes threaded housings into which the screws (or similar) are screwed, passing through the screw holes carried by the axial tabs. - the engine casing has a generally cylindrical shape. - the internal diameter of the skirt is greater than the diameter of the impeller so as to allow axial fitting of the skirt around the motor casing when the motor shaft carries the impeller. - the internal diameter of the skirt corresponds to the external diameter of the motor casing, that is to say they are approximately equal so as to allow axial fitting of the skirt around the motor casing. - the external diameter of the motor housing is greater than or equal to the diameter of the impeller. - the inner wall of the volute skirt fits the outer wall of the engine casing when the skirt is arranged, i.e. axially fitted, around the casing, i.e. the profile of the inner wall of the volute skirt is (approximately) complementary to the profile of the outer wall of the engine casing. at least one annular seal is arranged around the motor housing, i.e. around its perimeter or external periphery, said annular seal providing a fluid seal. the annular seal is made of elastomer. a striated annular area having raised patterns or shapes is arranged around the engine casing, that is to say around all or part of its perimeter or external periphery. The striated annular area includes raised patterns or shapes comprising alternating “peaks” and “valleys”. the axial tabs and the skirt are formed from a flexible material, such as plastic. The axial tabs are configured to deform slightly under the tightening force of the screws. the axial tabs each comprise a free end pressing on the peripheral external wall of the casing at the level of the striated annular zone, that is to say that the axial tabs of the skirt each comprise a free end pressing on the striated annular zone of the casing. the surface of the free ends of the axial tabs in contact with the grooved annular zone is configured to deform by matching the relief patterns so as to obtain a strong connection between the skirt and the casing. the deformation of the surface of the free ends is a function of the tightening force of the screws. the volute (including the skirt), the motor housing and the impeller are coaxial, i.e. arranged coaxially (axis AA). The impeller includes a central passage passing axially through the wheel at its center. the rotating motor shaft passes through the central passage of the impeller. The impeller is driven by the motor at a speed of up to 70,000 rpm, typically up to 40,000 rpm. the impeller is formed from a polymer material, preferably manufactured by injection. the wheel has a wheel thickness of between 0.5 and 1.5 mm, the thickness being the distance between the surfaces of the first and second faces of the impeller. - the electric motor casing forms a rigid frame or shell surrounding the rotor and stator of the motor. - the engine casing is made of metal or metal alloy, preferably aluminum alloy or steel. - the electric motor includes cables or electrical wires used for its electrical connection to a source of electric current supplying it with electric current. - during operation, the electric motor drives the impeller into rotation. - the electric motor is brushless. - the volute includes a gas inlet. - the volute gas inlet is located above the volute, i.e. opposite the engine. - the volute surmounts the electric motor; - the impeller is arranged to move in rotation within the compartment internal of the volute. - the volute includes a gas outlet orifice. - the gas outlet orifice is carried by an outlet duct in fluid communication with the internal compartment of the volute.

[0011] The invention also relates to a medical ventilator comprising a micro-blower according to the invention, that is to say a respiratory assistance device used to treat respiratory pathologies in humans.

[0012] The invention will now be better understood thanks to the following detailed description, given for illustrative but non-limiting purposes, with reference to the appended figures among which:

[0013] [fig. 1] is an external schematic view of a micro-blower according to the invention,

[0014] [fig.2] is a side view of a micro-blower according to the invention,

[0015] [fig.3] shows schematically the fitting of the volute on the casing of a micro-blower according to the invention,

[0016] [fig.4] shows the volute on the casing after fitting,

[0017] [fig.5] is a schematic sectional view of the volute and casing regions in contact after fitting, and

[0018] [fig.6] is a schematic sectional view of a medical ventilator incorporating a micro-blower according to the invention.

[0019] [fig.l] and [fig.2] diagram a motorized micro-blower 1 according to the invention for a medical ventilator 100, comprising a volute 2 surmounting an electric motor 3 arranged in a rigid casing 4, of generally cylindrical shape, serving to protect the motor 3, that is to say typically the stator and the rotor of the motor. The casing rigid 4 is preferably made of metal, for example steel or aluminum.

[0020] The electric motor 3 is preferably brushless and / or is designed to reach a rotation speed of up to 70,000 rpm, typically up to 40,000 rpm. The motor 3 is supplied with electric current, to enable its operation, in a conventional manner by means of suitable electrical connections, for example by means of connectors, sockets, wires or electrical cables, etc., enabling the medical ventilator and / or the micro-blower 1 to be connected to the electrical network or to one (or more) electrical power supply batteries.

[0021] During its operation, the motor of the micro-blower 1 rotates a motor shaft 15, also called 'axis', carrying a bladed wheel 5, also called 'bladed wheel', (see [fig.3] and [fig.4]) having a circular section with a diameter of between 20 and 80 mm, typically between 30 and 60 mm.

[0022] The impeller 5 generally comprises from 10 to 60 fins, typically from 10 to 30 fins approximately, arranged radially on one of the faces of the impeller 5, i.e. its upper face which is opposite the gas inlet 6 of the volute 2.

[0023] The impeller 5 is arranged so as to be movable in rotation within the internal compartment 9 of the volute 2 surmounting the electric motor 3 and the casing 4, so as to generate an air flow at a pressure higher than atmospheric pressure (> 1 atm).

[0024] Preferably, the impeller 5 and the volute 2 are made of polymer material(s), for example a plastic of the Acrylonitrile Butadiene Styrene or ABS, Polycarbonate or PC or Polyether Ether Ketone known as PEEK type.

[0025] The volute 2 typically has a circular section. The gas inlet 6 of the volute 2 communicates fluidically with the internal compartment 9 of the volute 2 so as to supply it with gas, typically air or an air / O2 mixture. The gas is sucked into the internal compartment 9, during the rotations of the wheel 5 which is driven in rotation by the motor shaft 15. A gas outlet orifice 7 ensures an outlet of the gas flow generated in the internal compartment 9 of the volute 2, during the rotations of the wheel 5. The gas outlet orifice 7 is carried by an outlet duct 8 in fluid communication with the internal compartment of the volute 2. The outlet duct 8 is preferably formed in one piece, for example by injection molding or the like, with the volute 2.

[0026] The gas flow is then sent to the patient via a gas circuit arranged in the ventilator, which is in fluid communication with, on the one hand, the air outlet duct 8 so as to convey the gas coming from the air outlet duct 8 and, on the other hand, with a flexible pipe (not shown) or the like connecting to the ventilator and making it possible to convey the gas to a respiratory interface, such as a breathing mask or similar (not shown) used to deliver the gas to the patient.

[0027] According to the present invention, the volute 2 comprises, at its base 11, that is to say on the side of its lower portion, a skirt 10 forming a sleeve around the casing 4, when the volute 2 is arranged on the casing 4 so as to surmount the casing 4 and the motor 3. In other words, the lower wall of the volute 2 is shaped into a skirt 10 which encircles, i.e. surrounds, the perimeter of the casing 4.

[0028] The volute 2 and the skirt 10 are advantageously formed from a single piece, for example by injection molding or other means. However, they could also be formed from several pieces fixed to each other.

[0029] The skirt 10 has a generally cylindrical shape, that is to say a circular section. The internal diameter of the skirt 10 and the external diameter of the casing 4 are approximately equal so as to be able to axially (axis AA) fit the skirt 10 of the volute 2 around the casing 4, that is to say that the internal profile of the skirt 10 corresponds to the external profile of the casing 4 so as to fit it when the skirt 10 is arranged around the casing 4, as shown in [fig.4].

[0030] As illustrated in [fig.5], after fitting the skirt 10 around the casing 4 of the motor 3, the volute 2, the casing 3 and the impeller 5 with blades are coaxial with axis AA, that is to say arranged coaxially.

[0031] The volute 2 is held integral with the casing 4 via fixing means, preferably by screwing, for example screws 12, bolts or the like. More precisely, the skirt 10 comprises one or more, preferably several, axial tabs 13, such as cutouts, formed through the wall of the skirt 10 and each having a screw orifice 14 through which a screw 12 passes, which screw 12 is then screwed into the wall of the casing 4, for example in a threaded housing 16.

[0032] Preferably, the skirt 10 comprises (at least) three axial tabs 13 equally angularly distributed around the periphery of the skirt 10 and each comprising a screw orifice 14 and the casing 4 of the motor 3 comprises three threaded housings 16 receiving the screws 12 or the like passing through the three screw orifices 14 drilled through the 3 axial tabs 13.

[0033] The axial tabs 13 are formed from longitudinal cutouts 18 made in pairs in the wall of the skirt 10, as illustrated in [fig.3] and [fig.4].

[0034] The axial tabs 13 are made of the same material as the skirt 10, preferably a slightly flexible plastic, such as a polymer of the ABS, PC or PEEK type, so as to have a flexibility allowing them to deform / bend slightly under the effect of tightening the fixing means, in particular screwing the screws 12 into the orifices 13 and the threaded housings 16.

[0035] Furthermore, in order to improve the grip of the axial tabs 13 around the casing 4 of the motor 3, at least one zone is provided around the periphery of the casing 4 ribbed annular 19, as illustrated in [fig.3] and [fig.4], forming a gripping strip all around the casing 4.

[0036] More precisely, as shown diagrammatically in [fig.5], when the volute 2 is fitted around the casing 4 of the motor 3, the skirt 10 forms a sleeve around the casing 4 by crushing the sealing gasket 17 in order to ensure a fluidic (i.e. gaseous) seal between the skirt 10 and the casing 4.

[0037] Furthermore, the axial tabs 13 which are formed of a slightly flexible material, such as a plastic, deform under the effect of the tightening force of the screws 12. The free ends 13a of the axial tabs 13 then come to bear on the peripheral external wall of the casing 4 at the level of the striated annular zone 19 which has raised patterns or shapes, such as an alternation of “peaks” and “valleys”. The surface of the free ends 13a of the axial tabs 13 in contact with the striated annular zone 19 then deforms by matching the raised patterns, which makes it possible to obtain a strong connection between the skirt 10 and the casing 4. The deformation of the surface of the free ends 13a is more or less significant depending on the tightening force of the screws 12.

[0038] Furthermore, one (or more) annular seals 17 are also provided, arranged around the casing 4 of the motor 3, i.e. around its external periphery. As can be seen in [fig.3], the annular seal 17 is located between the grooved annular zone 19 and the impeller 5. The annular seal 17 and the grooved annular zone 19 lie in planes parallel to each other and perpendicular to the axis AA.

[0039] As illustrated in [fig.4], once the motor 3 is capped, that is to say as soon as the volute 2 is installed on the casing 4, an adjustment of the clearance J is possible in the axis AA of the motor 3. The position is held temporarily by fitting, then it is the tightening of the screws 12 which locks the position of the volute 2 on the casing 4.

Claims

Claims

1. Micro-blower (1) for medical ventilator (100) comprising an electric motor (3) arranged in a casing (4) and a volute (2) arranged to surmount the electric motor (3), wherein the electric motor (3) comprises a rotating motor shaft (15) carrying a vaned wheel (5), and the volute (2) comprises an internal compartment (9) containing the vaned wheel (5), the volute (2) comprising a skirt (10) forming a sleeve around the casing (4) and secured to said casing (4), characterized in that: - the skirt (10) comprises several axial tabs (13) crossed by a screw hole (14), the skirt (10) being fixed to the casing (4) by screws (12) passing through the screw holes (14) carried by the axial tabs (13), and - a striated annular zone (19) having relief patterns is arranged around the casing (4) of the engine (3),the axial tabs (13) of the skirt (10) each comprising a free end (13a) pressing on the striated annular zone (19) of the casing (4).,

2. Micro-blower according to the preceding claim, characterized in that the skirt (10) is arranged at the base (11) of the volute (2).

3. Micro-blower according to one of the preceding claims, characterized in that the skirt (10) is formed in one piece with the volute (2), preferably the skirt (10) has a generally cylindrical shape.

4. Micro-blower according to one of the preceding claims, characterized in that the skirt (10) is formed from a material having flexibility, in particular a polymer.

5. Micro-blower according to one of the preceding claims, characterized in that at least one annular seal (17) is arranged around the casing (4) of the motor (3).

6. Medical ventilator (100) comprising a micro-blower (1) according to one of the preceding claims.

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